Flash external mp3 compression

Hi I m working on a project that requires flash buttons to play external mp3 files. Below is the code that i m using to achieve this. But when played sound files seems to be loaded slow and pauses occur during the play. I was wondering if there is a way to compress external mp3 files through flash, therefore minimizing the occurance of the pauses.


// Create sound instance and assign function to onLoad event
var song:Sound = new Sound();
song.onLoad = loadDone;
// Button onRelease event handler
startLoad.onRelease = function() {
    song.loadSound("mp3/addvocab1/tilessent.mp3", true);
    _root.onEnterFrame = loadProgress;
};